I have been using a program called 'Tagscan' made by xaudio to generate my ID3v1 tags (v2.00 hasn't complained about any of them yet).
Tagscan has worked great for me.... I make a practice of naming my files with a certain format.... this program has one mode where you can create tags based on the file name. You tell it the delimiters, element order, etc.... it also inserts other info it can figure out from the file, such as rate, duration, etc. Once you set it up, you just point it at a directory and it will batch process all mp3 files in it. It also gives you an option to recursively process all subdirectories in the directory you chose.
I haven't tried it, but it allows batch file renaming, editing of existing tags, etc. I don't know if it work with v2 tags or not, haven't tried it. The version I found is for Windows and is GUI based. Oh yeah, and it is free... no nags, etc.
The links below are for the version I am using if you want to give it a try.....
XAudio Website
Download TagScan from my site
XAudio's site seems to be down right now... so I threw it on my site. I don't have any HTML on my site linking the file, so if your browser doesn't automatically try to download it when you click the link, you should find somewhere else to get it pretty quickly by searching for 'Tagscan', with your fav serach engine.